1. Technical Field
The present disclosure relates to an optical photographing lens assembly, imaging unit and electronic device. More particularly, the present disclosure relates to a compact optical photographing lens assembly and imaging unit applicable to an electronic device.
2. Description of Related Art
In recent years, with the popularity of electronic devices having camera functionalities, the demand of miniaturized optical systems has been increasing. The sensor of a conventional optical system is typically a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact, optical systems have gradually evolved toward the field of higher megapixels, there is an increasing demand for compact optical systems featuring better image quality.
A conventional compact optical system in a portable electronic product typically utilizes a three-element lens structure. Due to the popularity of electronic products with high-end specifications, such as smart TVs, wireless monitoring devices, motion sensing input devices and other high-end electronic devices, the requirements for high resolution and image quality of present compact optical systems increase significantly. However, the conventional optical systems cannot satisfy these requirements of the compact optical systems.
Another conventional compact optical system provides a four-element lens structure. Since the first lens element has positive refractive power; therefore, it is not favorable for enlarging the field of view of the optical system. Furthermore, both of the second and the third lens elements have negative refractive powers, and the fourth lens element has positive refractive power. Therefore, it is not favorable for reducing the back focal length and keeping the optical system compact. Besides, the designs of the image-side surface of the first and the second lens elements result in worse image quality.
Inasmuch as the foregoing, a need exists in the art for having an optical system favorable for being applied to electronic products with large field of view and photographing functionality. In addition, it might be favorable for having good image quality and reducing the total track length of the optical system.